Internal combustion engine



FIG. 1 is a front perspective view of an internal combustion engineshowing our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a right side view thereof.

The ornamental design for an internal combustion engine, as shown anddescribed.